JPS6325306A - Tappet clearance confirming method - Google Patents

Abstract

PURPOSE:To reliably confirm the tappet clearance, by measuring a difference between a position where one end of a rocker arm comes into pressure contact with a cam and a position where an adjusting screw at the other end abuts against a valve stem, and measuring a value when the other end is lifted by an amount adding a valve spring load. CONSTITUTION:In confirming a tappet clearance of a rocker arm a, a presser member 6 is lowered so as to make a slipper surface at one end of the rocker arm a abut against a valve operating cam c. At the position of the rocker arm under this condition, a detection value of a displacement detecting means 4 is reset to zero. Then, the presser member is lifted, and an adjusting screw a1 at the other end of the rocker arm is brought into contact with a valve stem b. A quantity of displacement at this time is detected by the detecting means 4. Then, a hook 9 is engaged with the other end to lift the other end by an amount adding a valve spring load by means of a cylinder 10. In accordance with a value detected by the detecting means 4 at this time, a valve clearance is confirmed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is directed to a rocker arm which is used in an engine having a biased rocker arm metal, which includes an adjusting screw facing a knoble stem at one end and a slit A surface facing a valve operating cam at the other end. Concerning how to check tappet clearance.

(Conventional technology) Conventionally, when checking tappet clearance, a feeler gauge was inserted between the adjustment screw and the valve stem, and when the operator pulled it out, the operator could feel the slight resistance and check that the amount of tappet clearance was appropriate. I am trying to determine whether or not.

(Problem to be Solved by the Invention) By the way, the reason why the valve stem is pushed down against the valve spring is due to the valve mechanism, such as the clearance of the shaft support of the rocker arm, after the adjustment screw contacts the valve stem. The looseness is absorbed.

This is when the contact force of the adjusting screw against the knob stem increases to a value equivalent to the knob spring load, and the true value of the tappet clearance is determined by This is the total value of the clearance that occurs between the adjustment screw and the knob stem, and the backlash of the valve mechanism that is absorbed when an upward force equivalent to the valve spring load is applied to the adjustment screw. With the conventional method of using a feeler gauge, it is difficult to measure the true value of the entire tappet clearance, including play in the valve mechanism, and the resistance felt by the operator when inserting and removing the feeler gauge is difficult to measure. This is a type of sensory test to judge the suitability of tappet clearance based on its condition, and requires a high degree of skill and has poor workability, so it is desirable to be able to measure the true value of tappet clearance accurately and with good workability. Furthermore, it is desirable to be able to measure the amount of backlash in the valve mechanism. In other words, if the play in the valve mechanism is too large, it will easily wear out and its durability will deteriorate, making it necessary to replace parts, and the present invention is intended to be used as data for determining this.The present invention satisfies the above requirements. Its purpose is to provide all methods for checking tappet clearance.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an engine equipped with a rocker arm having an adjustment screw facing a valve stem at one end and a slotted nose face facing a moving cam at the other end. In the method of checking tappet clearance, press the other end of the rocker arm so that the slipper surface is in contact with the inside of the base of the valve train cam, then release the pressure on the other end and move the rocker arm so that the adjusting screw is aligned with the valve stem. The amount of displacement of the attachment part of the adjustment screw of the rocker arm when it swings in response to the contact state, and the displacement of the attachment part from the valve stem with the adjustment screw in contact with the valve stem by a force equivalent to the valve spring load. The present invention is characterized in that the amount of displacement of the attachment portion when the attachment portion is pulled up in the direction of the attachment portion is detected.

(Function) When the rocker arm is swung from the state in which the slipper surface is in contact with the inside of the base of the valve cam to the state in which the adjustment screw is in contact with the valve stem, the amount of displacement of the attachment part of the adjustment screw is 1.
Then, h4 is equal to the clearance created between the adjusting screw and the valve stem when the slipper surface is brought into contact with the inside of the base of the valve cam.

Dad, when you pull up the mounting part of the adjustment screw from the state where the adjustment screw is in contact with the valve stem, when the mounting part is pulled up by tl, the l< surface will come into contact with the inside of the base,
Due to the backlash of the relief valve mechanism, the mounting part is further displaced upward by tl, and since the lifting force is equal to the valve spring load, tl is the amount when a lifting force equivalent to the valve spring load is applied to the adjustment screw. Therefore, if the displacement amount t3 (t3 = 4 + t2) when the mounting part is pulled up is detected, this becomes the true value of the tappet clearance, and from t3 the clearance amount can be calculated. Can accurately determine suitability.

Also, from t3 to 1. By subtracting it, it is possible to detect tl, that is, the size of the backlash in the forgiveness mechanism, and it is also possible to determine whether or not the backlash bond is appropriate.

(Example) Referring to FIG. 1, a shows a rocker arm that is installed on the engine's cylinder head, and an adjusting screw al and its fixing nut a2 are attached to one end of the rocker arm a, facing the valve stem b. At the same time, a slipper surface a3 facing the valve drive cam is formed at the other end, and the rotation of the valve drive cam C pushes down the valve stem b through the rocker arm a against the valve spring b1. The valve mechanism is configured such that tappet clearance adjustment and tappet clearance confirmation after adjustment can be performed on the same stage using a tappet clearance adjustment device placed above the cylinder head.

The adjustment device includes a first movable frame (1) that is vertically movable in a direction substantially along the axis of the valve stem b, and a first movable frame that is vertically movable directly above the valve drive cam C. 2 movable frame (2), the first movable frame (1) is provided with an operating means (3) for the adjustment screw al, and the second movable frame (2) is provided with a predetermined detection device on one end side of the rocker arm a. A/bK adjustment means (4) is provided for detecting the displacement of the part a4, and while the detecting means (4) detects the displacement of the detecting part a4, the operating means (3) temporarily adjusts the adjusting screw al. b is valve spring b
The tappet clearance is adjusted by tightening the tappet until it is pushed down against the pressure 1 and then loosening the adjusting screw al by a predetermined amount.

The operating means (3) is a driver (3) driven by a servo motor (not shown) mounted on the upper part of the first movable frame (1).
a) and a nut runner (not shown) on the movable frame (1)
The socket (3c) is spline-engaged with the lower end of the output shaft (3b) of the driver 4, and the bar (3a) is made to protrude into the socket (3C) through the output shaft (3b). ) (3c) to the fixing nut a2 and the screwdriver (3a) to the adjusting screw, and in the next state, first reverse the socket (3c) and loosen the fixing nut 1.
Next, rotate the screwdriver (3a) to tighten the adjustment screw al.
After tightening as above, loosen the socket, and finally tighten the socket (3c
) in the normal direction to tighten the fixing nut a2.

The displacement detection means (4) is composed of a sensor capable of detecting the displacement of the lower end measuring element (4a) on the order of microns, and is mounted on a bracket (2) fixed to the second movable frame (2).
At the same time, a swinging arm (5) is attached to the platen (2a) at the lower end of the platen (2a) and is urged downward by a spring (5b) with @(5a) as a fulcrum.
A contact seat (5c) that comes into contact with the upper surface of one end of the rocker arm a is formed at the tip of the contact point (5c), and the contact point (4) is placed on the corresponding seat (5c).
a), thus the rocker arm a of the corresponding seat (5c)
The detection means (4) detects the displacement of the abutting part of the rocker arm a as a detection part a4, and multiplies the detected value by the ratio of the distance between the adjustment screw al and the detection part a4 to the cap fulcrum of the rocker arm a. The amount of displacement of the OZ adjustment screw al mounting part was measured.

In addition, the second movable frame (2) has a cylinder (6) formed therein.
A pressing piece (6) is provided which is moved up and down via the piston rod (6b), and when adjusting the above-mentioned tappet clearance, the pressing piece (6) pushes down the other end of the rocker arm 2, and the slipper The surface a3 is kept in contact with the inside of the base of the banben cam C.

In addition, the adjustment screw a of the rocker arm a is attached to the first movable frame (1).
A pulling means (7) is provided which can freely pull up the mounting portion of the valve stem (1) in a direction away from the valve stem (b). A tilting frame (8) that can be tilted in the lateral direction using the shaft (8a) as a fulcrum is installed on the lower part of the tilting frame (8), and a hook that can be secured to the lower surface of the mounting screw al is provided at the lower part of the tilting frame (8). (9)
A piston rod (10 m) extending downward from a lifting cylinder GO formed at the top of the tilting frame (3) is inserted into the hook (9) so as to be movable up and down, and connected to the upper end of the hook (9). The cylinder QQ can be pulled up with a force equivalent to the valve spring load, and the bracket (l
Attach a fixed frame surround to a) by positioning it on the lateral side of the tilting frame (8), and move the wedge piece (12a) that comes into contact with the lower lateral side of the tilting frame (8) up and down on the fixed frame αυ. A tilting cylinder steepness is formed, and according to the downward movement of the wedge piece (12a), the tilting frame (
8) is a spring (8b) inserted between this and the fixed frame α℃.
) is tilted counterclockwise in the drawing against the hook (9
) is engaged with the lower surface of the attachment of the adjusting screw al as shown in the second figure, and in this state the lifting cylinder QO is operated. It was made to be able to be pulled up with a force equivalent to the load.

Next, to explain the operation of the above embodiment, after adjusting the tappet clearance, the displacement detecting means (
4), reset the detected value to zero, then move the pressing piece (6) upward, push down one end of the rocker arm a with the biasing force of the spring (5b) of the swing arm (5), and tighten the adjustment screw al. The adjusting screw al is brought into contact with the pulp stem b, and the amount of displacement of the mounting portion of the adjusting screw al at this time is detected by the detecting means (4). This amount of displacement is determined by the clearance 1.0 that occurs between the adjusting screw al and the pulp stem b when the slipper surface a3 is brought into contact with the inside of the base of the stop valve cam C. is equal to

Then, by means of the pulling means (7), the adjusting screw a is
1 is pulled up with a force corresponding to the valve spring load, and the amount of displacement of the mounting part due to the lifting is determined from the difference between the detected value of the detection means (4) before and after the pulling up. This amount of displacement is determined by the adjustment screw a, as explained in the section of the function above.
The value t3. is the sum of the clearance t1 and the backlash t1 of the valve mechanism that is absorbed when a force equivalent to the pulp spring load is applied to t3.l. In other words, it is the true value of tappet clearance9. Thus, from this displacement tts, it is possible to accurately determine whether the tappet clearance amount is appropriate.

Further, by subtracting ts from ts, it is possible to detect t2, that is, the backlash of the valve mechanism, and it is also possible to determine whether or not the play is appropriate.

(Effects of the Invention) As described above, according to the present invention, the true value of the tappet clearance including play in the valve mechanism can be detected accurately and with good workability without worrying about the senses of the operator, and whether or not the amount of tappet clearance is appropriate can be detected. In addition to being able to accurately determine the amount of backlash in the valve train, it is also possible to independently detect the amount of backlash in the valve mechanism and determine whether or not the backlash is appropriate.

In addition, it has the effect of facilitating the automation of confirmation work.

[Brief explanation of the drawing]

FIG. 1 is a cut-away side view of an example of a device used for carrying out the present invention, and FIG. 2 is a cut-away side view of its main parts in an operating state. a...Rocker arm al...Adjustment screw a3...
-Slipper surface b...Pulp stem b1...Pulp fling C...Valve cam (4)...Displacement detection means (7)...Lifting means Figure 1

Claims (1)

[Claims] In a method for checking the tappet clearance of an engine equipped with a rocker arm having an adjusting screw facing the valve stem at one end and a slipper surface facing a moving cam at the other end, the slipper surface is moved by pressing the other end of the rocker arm. The amount of displacement of the mounting part of the adjustment screw of the rocker arm when the pressure on the other end is released from the state where it is in contact with the inside of the base of the valve cam and the rocker arm is swung to the state where the adjustment screw is in contact with the valve stem. , the amount of displacement of the mounting portion is detected when the adjustment screw is brought into contact with the valve stem and the mounting portion is pulled up in a direction away from the valve stem with a force equivalent to the valve spring load. A tappet clearance confirmation method featuring: